The part of the Earth’s interior between the core and the crust composed of dense silicate rocks. The upper surface of the mantle is the Moho discontinuity characterized by a sharp increase in P-wave velocity to 8.1±0.2 km/s. The density of the mantle is about 3.3–3.4 g/cm3 and the mantle is essentially non-magnetic. The mantle includes the lower lithosphere and the asthenosphere. Below the mantle is the core separated from the mantle by the Gutenberg-Weichert discontinuity. See Figure E-1.